fil0fil.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

/******************************************************
The tablespace memory cache

(c) 1995 Innobase Oy

Created 10/25/1995 Heikki Tuuri
*******************************************************/

#include "fil0fil.h"

#include "mem0mem.h"
#include "sync0sync.h"
#include "hash0hash.h"
#include "os0file.h"
#include "os0sync.h"
#include "mach0data.h"
#include "ibuf0ibuf.h"
#include "buf0buf.h"
#include "buf0flu.h"
#include "buf0lru.h"
#include "log0log.h"
#include "log0recv.h"
#include "fsp0fsp.h"
#include "srv0srv.h"
#include "srv0start.h"
#include "mtr0mtr.h"
#include "mtr0log.h"
#include "dict0dict.h"

	 
/*
		IMPLEMENTATION OF THE TABLESPACE MEMORY CACHE
		=============================================

The tablespace cache is responsible for providing fast read/write access to
tablespaces and logs of the database. File creation and deletion is done
in other modules which know more of the logic of the operation, however.

A tablespace consists of a chain of files. The size of the files does not
have to be divisible by the database block size, because we may just leave
the last incomplete block unused. When a new file is appended to the
tablespace, the maximum size of the file is also specified. At the moment,
we think that it is best to extend the file to its maximum size already at
the creation of the file, because then we can avoid dynamically extending
the file when more space is needed for the tablespace.

A block's position in the tablespace is specified with a 32-bit unsigned
integer. The files in the chain are thought to be catenated, and the block
corresponding to an address n is the nth block in the catenated file (where
the first block is named the 0th block, and the incomplete block fragments
at the end of files are not taken into account). A tablespace can be extended
by appending a new file at the end of the chain.

Our tablespace concept is similar to the one of Oracle.

To acquire more speed in disk transfers, a technique called disk striping is
sometimes used. This means that logical block addresses are divided in a
round-robin fashion across several disks. Windows NT supports disk striping,
so there we do not need to support it in the database. Disk striping is
implemented in hardware in RAID disks. We conclude that it is not necessary
to implement it in the database. Oracle 7 does not support disk striping,
either.

Another trick used at some database sites is replacing tablespace files by
raw disks, that is, the whole physical disk drive, or a partition of it, is
opened as a single file, and it is accessed through byte offsets calculated
from the start of the disk or the partition. This is recommended in some
books on database tuning to achieve more speed in i/o. Using raw disk
certainly prevents the OS from fragmenting disk space, but it is not clear
if it really adds speed. We measured on the Pentium 100 MHz + NT + NTFS file
system + EIDE Conner disk only a negligible difference in speed when reading
from a file, versus reading from a raw disk. 

To have fast access to a tablespace or a log file, we put the data structures
to a hash table. Each tablespace and log file is given an unique 32-bit
identifier.

Some operating systems do not support many open files at the same time,
though NT seems to tolerate at least 900 open files. Therefore, we put the
open files in an LRU-list. If we need to open another file, we may close the
file at the end of the LRU-list. When an i/o-operation is pending on a file,
the file cannot be closed. We take the file nodes with pending i/o-operations
out of the LRU-list and keep a count of pending operations. When an operation
completes, we decrement the count and return the file node to the LRU-list if
the count drops to zero. */

/* When mysqld is run, the default directory "." is the mysqld datadir,
but in the MySQL Embedded Server Library and ibbackup it is not the default
directory, and we must set the base file path explicitly */
const char*	fil_path_to_mysql_datadir	= ".";

/* The number of fsyncs done to the log */
ulint	fil_n_log_flushes                       = 0;

ulint	fil_n_pending_log_flushes		= 0;
ulint	fil_n_pending_tablespace_flushes	= 0;

/* Null file address */
fil_addr_t	fil_addr_null = {FIL_NULL, 0};

/* File node of a tablespace or the log data space */
struct fil_node_struct {
	fil_space_t*	space;	/* backpointer to the space where this node
				belongs */
	char*		name;	/* path to the file */
	ibool		open;	/* TRUE if file open */
	os_file_t	handle;	/* OS handle to the file, if file open */
	ibool		is_raw_disk;/* TRUE if the 'file' is actually a raw
				device or a raw disk partition */
	ulint		size;	/* size of the file in database pages, 0 if
				not known yet; the possible last incomplete
				megabyte may be ignored if space == 0 */
	ulint		n_pending;
				/* count of pending i/o's on this file;
				closing of the file is not allowed if
				this is > 0 */
	ulint		n_pending_flushes;
				/* count of pending flushes on this file;
				closing of the file is not allowed if
				this is > 0 */	
	ib_longlong	modification_counter;/* when we write to the file we
				increment this by one */
	ib_longlong	flush_counter;/* up to what modification_counter value
				we have flushed the modifications to disk */
	UT_LIST_NODE_T(fil_node_t) chain;
				/* link field for the file chain */
	UT_LIST_NODE_T(fil_node_t) LRU;
				/* link field for the LRU list */
	ulint		magic_n;
};

#define	FIL_NODE_MAGIC_N	89389

/* Tablespace or log data space: let us call them by a common name space */
struct fil_space_struct {
	char*		name;	/* space name = the path to the first file in
				it */
	ulint		id;	/* space id */
	ib_longlong	tablespace_version;
				/* in DISCARD/IMPORT this timestamp is used to
				check if we should ignore an insert buffer
				merge request for a page because it actually
				was for the previous incarnation of the
				space */
	ibool		mark;	/* this is set to TRUE at database startup if
				the space corresponds to a table in the InnoDB
				data dictionary; so we can print a warning of
				orphaned tablespaces */
	ibool		stop_ios;/* TRUE if we want to rename the .ibd file of
				tablespace and want to stop temporarily
				posting of new i/o requests on the file */
	ibool		stop_ibuf_merges;
				/* we set this TRUE when we start deleting a
				single-table tablespace */
	ibool		is_being_deleted;
				/* this is set to TRUE when we start
				deleting a single-table tablespace and its
				file; when this flag is set no further i/o
				or flush requests can be placed on this space,
				though there may be such requests still being
				processed on this space */
	ulint		purpose;/* FIL_TABLESPACE, FIL_LOG, or FIL_ARCH_LOG */
	UT_LIST_BASE_NODE_T(fil_node_t) chain;
				/* base node for the file chain */
	ulint		size;	/* space size in pages; 0 if a single-table
				tablespace whose size we do not know yet;
				last incomplete megabytes in data files may be
				ignored if space == 0 */ 
	ulint		n_reserved_extents;
				/* number of reserved free extents for
				ongoing operations like B-tree page split */
	ulint		n_pending_flushes; /* this is > 0 when flushing
				the tablespace to disk; dropping of the
				tablespace is forbidden if this is > 0 */
	ulint		n_pending_ibuf_merges;/* this is > 0 when merging
				insert buffer entries to a page so that we
				may need to access the ibuf bitmap page in the
				tablespade: dropping of the tablespace is
				forbidden if this is > 0 */
	hash_node_t	hash; 	/* hash chain node */
	hash_node_t	name_hash;/* hash chain the name_hash table */
	rw_lock_t	latch;	/* latch protecting the file space storage
				allocation */
	UT_LIST_NODE_T(fil_space_t) unflushed_spaces;
				/* list of spaces with at least one unflushed
				file we have written to */
	ibool		is_in_unflushed_spaces; /* TRUE if this space is
				currently in the list above */
	UT_LIST_NODE_T(fil_space_t) space_list;
				/* list of all spaces */
	ibuf_data_t*	ibuf_data;
				/* insert buffer data */
	ulint		magic_n;
};

#define	FIL_SPACE_MAGIC_N	89472

/* The tablespace memory cache; also the totality of logs = the log data space,
is stored here; below we talk about tablespaces, but also the ib_logfiles
form a 'space' and it is handled here */

typedef	struct fil_system_struct	fil_system_t;
struct fil_system_struct {
	mutex_t		mutex;		/* The mutex protecting the cache */
	hash_table_t*	spaces;		/* The hash table of spaces in the
					system; they are hashed on the space
					id */
	hash_table_t*	name_hash;	/* hash table based on the space
					name */
	UT_LIST_BASE_NODE_T(fil_node_t) LRU;
					/* base node for the LRU list of the
					most recently used open files with no
					pending i/o's; if we start an i/o on
					the file, we first remove it from this
					list, and return it to the start of
					the list when the i/o ends;
					log files and the system tablespace are
					not put to this list: they are opened
					after the startup, and kept open until
					shutdown */
	UT_LIST_BASE_NODE_T(fil_space_t) unflushed_spaces;
					/* base node for the list of those
					tablespaces whose files contain
					unflushed writes; those spaces have
					at least one file node where
					modification_counter > flush_counter */
	ulint		n_open;		/* number of files currently open */
	ulint		max_n_open;	/* n_open is not allowed to exceed
					this */
	ib_longlong	modification_counter;/* when we write to a file we
					increment this by one */
	ulint		max_assigned_id;/* maximum space id in the existing
					tables, or assigned during the time
					mysqld has been up; at an InnoDB
					startup we scan the data dictionary
					and set here the maximum of the
					space id's of the tables there */
	ib_longlong	tablespace_version;
					/* a counter which is incremented for
					every space object memory creation;
					every space mem object gets a
					'timestamp' from this; in DISCARD/
					IMPORT this is used to check if we
					should ignore an insert buffer merge
					request */
	UT_LIST_BASE_NODE_T(fil_space_t) space_list;
					/* list of all file spaces */
};

/* The tablespace memory cache. This variable is NULL before the module is
initialized. */
fil_system_t*	fil_system	= NULL;

/* The tablespace memory cache hash table size */
#define	FIL_SYSTEM_HASH_SIZE	50 /* TODO: make bigger! */


/************************************************************************
NOTE: you must call fil_mutex_enter_and_prepare_for_io() first!

Prepares a file node for i/o. Opens the file if it is closed. Updates the
pending i/o's field in the node and the system appropriately. Takes the node
off the LRU list if it is in the LRU list. The caller must hold the fil_sys
mutex. */
static
void
fil_node_prepare_for_io(
/*====================*/
	fil_node_t*	node,	/* in: file node */
	fil_system_t*	system,	/* in: tablespace memory cache */
	fil_space_t*	space);	/* in: space */
/************************************************************************
Updates the data structures when an i/o operation finishes. Updates the
pending i/o's field in the node appropriately. */
static
void
fil_node_complete_io(
/*=================*/
	fil_node_t*	node,	/* in: file node */
	fil_system_t*	system,	/* in: tablespace memory cache */
	ulint		type);	/* in: OS_FILE_WRITE or OS_FILE_READ; marks
				the node as modified if
				type == OS_FILE_WRITE */
/***********************************************************************
Checks if a single-table tablespace for a given table name exists in the
tablespace memory cache. */
static
ulint
fil_get_space_id_for_table(
/*=======================*/
				/* out: space id, ULINT_UNDEFINED if not
				found */
	const char*	name);	/* in: table name in the standard
				'databasename/tablename' format */


/***********************************************************************
Returns the version number of a tablespace, -1 if not found. */

ib_longlong
fil_space_get_version(
/*==================*/
			/* out: version number, -1 if the tablespace does not
			exist in the memory cache */
	ulint	id)	/* in: space id */
{
	fil_system_t*	system		= fil_system;
	fil_space_t*	space;
	ib_longlong	version		= -1;

	ut_ad(system);

	mutex_enter(&(system->mutex));

	HASH_SEARCH(hash, system->spaces, id, space, space->id == id);

	if (space) {
		version = space->tablespace_version;
	}

	mutex_exit(&(system->mutex));

	return(version);
}

/***********************************************************************
Returns the latch of a file space. */

rw_lock_t*
fil_space_get_latch(
/*================*/
			/* out: latch protecting storage allocation */
	ulint	id)	/* in: space id */
{
	fil_system_t*	system		= fil_system;
	fil_space_t*	space;

	ut_ad(system);

	mutex_enter(&(system->mutex));

	HASH_SEARCH(hash, system->spaces, id, space, space->id == id);

	ut_a(space);

	mutex_exit(&(system->mutex));

	return(&(space->latch));
}

/***********************************************************************
Returns the type of a file space. */

ulint
fil_space_get_type(
/*===============*/
			/* out: FIL_TABLESPACE or FIL_LOG */
	ulint	id)	/* in: space id */
{
	fil_system_t*	system		= fil_system;
	fil_space_t*	space;

	ut_ad(system);

	mutex_enter(&(system->mutex));

	HASH_SEARCH(hash, system->spaces, id, space, space->id == id);

	ut_a(space);

	mutex_exit(&(system->mutex));

	return(space->purpose);
}

/***********************************************************************
Returns the ibuf data of a file space. */

ibuf_data_t*
fil_space_get_ibuf_data(
/*====================*/
			/* out: ibuf data for this space */
	ulint	id)	/* in: space id */
{
	fil_system_t*	system		= fil_system;
	fil_space_t*	space;

	ut_ad(system);

	ut_a(id == 0);

	mutex_enter(&(system->mutex));

	HASH_SEARCH(hash, system->spaces, id, space, space->id == id);

	mutex_exit(&(system->mutex));

	ut_a(space);

	return(space->ibuf_data);
}

/**************************************************************************
Checks if all the file nodes in a space are flushed. The caller must hold
the fil_system mutex. */
static
ibool
fil_space_is_flushed(
/*=================*/
				/* out: TRUE if all are flushed */
	fil_space_t*	space)	/* in: space */
{
	fil_node_t*	node;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(fil_system->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	node = UT_LIST_GET_FIRST(space->chain);

	while (node) {
		if (node->modification_counter > node->flush_counter) {

			return(FALSE);
		}

		node = UT_LIST_GET_NEXT(chain, node);
	}

	return(TRUE);
}

/***********************************************************************
Appends a new file to the chain of files of a space. File must be closed. */

void
fil_node_create(
/*============*/
	const char*	name,	/* in: file name (file must be closed) */
	ulint		size,	/* in: file size in database blocks, rounded
				downwards to an integer */
	ulint		id,	/* in: space id where to append */
	ibool		is_raw)	/* in: TRUE if a raw device or
				a raw disk partition */
{
	fil_system_t*	system	= fil_system;
	fil_node_t*	node;
	fil_space_t*	space;

	ut_a(system);
	ut_a(name);

	mutex_enter(&(system->mutex));

	node = mem_alloc(sizeof(fil_node_t));

	node->name = mem_strdup(name);
	node->open = FALSE;

	ut_a(!is_raw || srv_start_raw_disk_in_use);

	node->is_raw_disk = is_raw;
	node->size = size;
	node->magic_n = FIL_NODE_MAGIC_N;
	node->n_pending = 0;
	node->n_pending_flushes = 0;

	node->modification_counter = 0;
	node->flush_counter = 0;
	
	HASH_SEARCH(hash, system->spaces, id, space, space->id == id);

	if (!space) {
		ut_print_timestamp(stderr);
		fprintf(stderr,
"  InnoDB: Error: Could not find tablespace %lu for\n"
"InnoDB: file ", (ulong) id);
		ut_print_filename(stderr, name);
		fputs(" in the tablespace memory cache.\n", stderr);
		mem_free(node->name);